1. Field of the Invention
The present invention relates to a balance control mechanism for restraining the lateral swinging of a carrier body of an overhead traveling carrier upon travel of the latter on a curved portion of an overhead rail.
2. Description of the Related Art
In a factory or the like, an overhead traveling carrier is used to transport an article from one place to another by moving it on wheels along an overhead rail. When it travels along a curved portion of the rail, the carrier is liable to be swung laterally due to a carrier body thereof or an article loaded on the body, leaned by exerted centrifugal force.
For preventing such lateral swinging of a carrier body, an arrangement is proposed in Japanese Utility Model Post-Exam Publication No. HEI 8-8938. The proposed arrangement comprises auxiliary overhead rails provided on both sides of a curved portion of an overhead rail, and auxiliary traveling rolls disposed on the right and left sides of an overhead traveling carrier for being held against the auxiliary overhead rails to thereby prevent the lateral swinging of the carrier body.
In the proposed arrangement, however, a centrifugal force exerted to the carrier body upon passage of the latter over a curved portion of the overhead rail is killed by the auxiliary overhead rails via the auxiliary traveling rolls. Thus, when the overhead rail has a small radius of curvature, large centrifugal force is exerted to the carrier body, thereby requiring the carrier body and auxiliary overhead rails to have increased rigidity.
For increasing the rigidity of the carrier body and auxiliary overhead rails, they need to be increased in weight and size, thereby increasing the cost of production. Otherwise, the overhead traveling carrier must be operated to travel along the curved rail portion at a low speed, thereby making the cycle of article transport prolonged.